CN108778409B

CN108778409B - Method and system for improving provision of electrical stimulation

Info

Publication number: CN108778409B
Application number: CN201780014480.9A
Authority: CN
Inventors: 布雷特·温吉尔; 肖恩·拉泽克; 凯文·巴布科克; 艾伦·法恩伯格; 里奇·洛温伯格; 帕特里克·沃尔贝
Original assignee: Halo Neuro Inc
Current assignee: Harlow Abc Co ltd; Flow Neuroscience AB
Priority date: 2016-02-08
Filing date: 2017-02-07
Publication date: 2022-04-08
Anticipated expiration: 2037-02-07
Also published as: EP3413966A4; US11400290B2; EP3413966A1; US20190247655A1; CN108778409A; US10315033B2; US20170224991A1; WO2017139243A1; US20220032054A1

Abstract

A method and system for providing stimulation to a user, the method comprising: transitioning the stimulation device from a baseline state to a first impedance monitoring state; during a first impedance monitoring state, direct adjustment of a position of the stimulation device at a head region of the user to meet a first impedance criterion; transitioning the stimulation device from a first impedance monitoring state to a stimulation mode when the first impedance criteria are met, the stimulation mode including a second monitoring state having second criteria; upon detecting that the second criterion is not fulfilled, transitioning the stimulation device from the stimulation mode to a first impedance monitoring state; and transitioning the stimulation device from the first impedance monitoring state to the stimulation mode upon detecting a third impedance criterion that satisfies the first impedance monitoring state.

Description

Method and system for improving provision of electrical stimulation

Cross Reference to Related Applications

This application claims benefit of U.S. provisional application serial No.62/292,511 filed on month 8, 2016 and U.S. provisional application serial No.62/442,350 filed on month 4, 2017, which are incorporated herein by reference in their entirety.

Technical Field

The present invention relates generally to the field of neuromodulation, and more particularly to new and useful methods for improving the provision of electrical stimulation.

Background

Electrode systems in the field of neuromodulation are used to transmit electrical signals to a subject and may be used to detect or measure signals from a subject. However, current electrode systems for electrical stimulation and/or signal detection are inadequate for a number of reasons, including inadequate monitoring of stimulation-associated parameters during stimulation, lack of safety features in non-clinical settings, inadequate contact between the subject and the electrodes of the system, inadequate notification and/or guidance to the subject when contact is inadequate, inadequate contact between the subject and the electrodes of the system, discomfort to the subject when the electrode system is used, and/or limited use in multiple electrical stimulation or biological signal detection paradigms. Furthermore, the methods of providing electrical stimulation also do not provide a positive user experience, do not adequately mitigate the effects of voltage or current transients, and do not provide control over other waveform aspects. Thus, current neuromodulation systems are inadequate for a number of reasons.

Accordingly, there is a need in the neuromodulation art for new and useful methods and systems to improve the provision of electrical stimulation. The present invention provides such a new and useful system and method.

Brief Description of Drawings

Fig. 1 depicts a schematic diagram of an embodiment of a method for improving the provision of electrical stimulation;

fig. 2 depicts an example of impedance, current and voltage behavior in an example of a method for improving the provision of electrical stimulation;

fig. 3 depicts an example current pulse output in an example of a method for improving the provision of electrical stimulation;

figure 4 depicts a variation of components implemented in a method for improving the provision of electrical stimulation;

fig. 5 depicts an example of application features implemented in a method for improving the provision of electrical stimulation;

fig. 6A depicts an embodiment of a system for improving the provision of electrical stimulation;

fig. 6B depicts an example of various system components in a system for improving the provision of electrical stimulation;

fig. 7A-7B depict example electronic diagrams associated with a system for improving the provision of electrical stimulation.

Description of the preferred embodiments

The following description of the preferred embodiments of the present invention is not intended to limit the present invention to these preferred embodiments, but rather to enable any person skilled in the art to make and use the present invention.

1. Method of producing a composite material

As shown in fig. 1, an embodiment of a method 100 for providing electrical stimulation to a user includes: transitioning the electro-stimulation device from the baseline state to a first impedance monitoring state upon activation of the electro-stimulation device S110; directing with the controller, during the first impedance monitoring state, an adjustment of the position of the electro-stimulation device at the body area of the user until a first impedance criterion associated with the first impedance monitoring state is met S120; transitioning the electro-stimulation device from the first impedance monitoring state to a stimulation mode when the first impedance criteria are met, the stimulation mode including a second monitoring state having second criteria, wherein the stimulation mode provides an electro-stimulation session to the user according to a set of waveform characteristics S130; upon detecting that the second criterion is not met, transitioning the electro-stimulation device from the stimulation mode to a first impedance monitoring state S140; and upon detecting that the third impedance criteria satisfy the first impedance monitoring state, transitioning the electro-stimulation device from the first impedance monitoring state to a stimulation mode S150 (e.g., resuming the electro-stimulation session of block S130).

The method 100 is used to provide a means for impedance monitoring in an electrical stimulation system with the objective of improving the safety and/or effectiveness of the electrical stimulation therapy. Thus, as the user performs a training activity (e.g., athletic performance training, motor skill training, other cognitive-related tasks, etc.), the method 100 may strategically and automatically monitor the provision of electrical stimulation therapy delivered to the user, where the electrical stimulation therapy is provided within specified therapy limits (e.g., in view of maximizing the efficacy of the electrical stimulation therapy, for safety, etc.). However, the method 100 may additionally or alternatively function to increase the effectiveness of the electrical stimulation therapy provided to the user, or proactively alert the user of conditions that may prevent delivery of a prescribed amount of neural stimulation by ensuring that the impedance parameters of the device-user body interface are within appropriate ranges during the course of the stimulation therapy.

In other variations, the method 100 may be used to enhance the effectiveness of electrical stimulation in cooperation with a user performing a task of interest, so as to enhance one or more of: an action ability (e.g., dexterity, coordination), a memory (e.g., working memory, declarative memory), a cognitive ability (e.g., mathematical ability), a learning (e.g., language learning, speech learning), a concentration, an attention, a creativity, and/or any other suitable cognitively associated attribute. In some specific applications, the method 100 may be used to increase the neuroplasticity of an athlete attempting to improve performance associated with a set of skills. Additionally or alternatively, the method 100 may be used to increase the neuroplasticity of a stroke patient during rehabilitation, increase the effectiveness of a treatment session for patients with paralyzed neurological disorders, and/or increase the neuroplasticity of an elderly user.

Preferably, at least a portion of the method 100 is configured to be implemented for a user outside of a clinical (e.g., hospital) or research (e.g., laboratory) environment, such that the user may be in a non-human environment while she or he is performing a set of tasks and/or receiving electrical stimulation therapy. Additionally or alternatively, the method 100 may be implemented in a full clinical or research setting, such as a physical therapy clinic.

The method may be implemented at least in part using a system comprising an electro-stimulation device having a body-mountable portion and a set of electrodes coupled to the body-mountable portion, the electro-stimulation device being operable between a baseline state, a first impedance monitoring state and a stimulation mode having a second monitoring state, wherein the first impedance monitoring state comprises a first set of impedance criteria and is accessible under at least one of the following conditions: a) detecting activation of the electro-stimulation device and b) not satisfying the impedance criteria of the second monitored state during the stimulation mode, and wherein the stimulation mode provides a stimulation session with waveform definition to the head region of the user when at least one of the first set of impedance criteria of the first impedance monitored state is satisfied. The system may also include a controller that sends the stimulation waveform definition and, in cooperation with the first impedance monitoring state, directs adjustment of the set of electrodes at the head region of the user.

Thus, the method 100 may be implemented by a system that is portable and comfortably worn by a patient while the patient performs a set of tasks (e.g., athlete performance training tasks, memory improvement tasks, etc.). Method 100 may be implemented, at least in part, using embodiments, variations, and examples of the system described in the following documents: section 2 below and/or U.S. application 14/470,683 entitled "Electrode System for Electrical Stimulation" and filed on 8/27 2014; U.S. application No.14/470,747 entitled "Method and System for Providing Electrical Stimulation to a User"; U.S. application No.62/292,511 entitled "Stimulation System and Method" and filed on 8/2/2016; U.S. application No.62/442,350 entitled "Stimulation System and Method" and filed on 2017, 1, 4; U.S. application No.14/878,647 entitled "Electrode System for Electrical Stimulation" and filed on 8/10/2015; U.S. application No.15/059,095 entitled "Method and System for Providing Electrical Stimulation to a User" and filed on 2016, 3, 2; and U.S. application No.15/335,240 entitled "Electrode position System and Method" filed on 2016, 10, 26, which is hereby incorporated by reference in its entirety. However, method 100 may be implemented using any other suitable stimulation system having a controller (e.g., a wearable stimulation system).

1.1 method-impedance monitoring and device localization

Block S110 recites: upon activation of the electro-stimulation device, the electro-stimulation device is transitioned from the baseline state to a first impedance monitoring state. Block S110 is used to provide an initial mode of impedance check when the electro-stimulation device is ready for use, to facilitate proper positioning of the device at the body region of the user in block S120.

The electro-stimulation device of block S110 preferably comprises an electro-stimulation device comprising a head-mountable portion reversibly or permanently coupled to one or more electrodes, the electro-stimulation device being in communication with a controller (e.g., a controller implemented at least in part using an application executed at a mobile computing device of a user). Embodiments, variations and examples of stimulation systems are described in one or more applications of the U.S. application: U.S. application 14/470,683 entitled "Electrode System for Electrical Stimulation" and filed on 27/8/2014; U.S. application No.14/470,747 entitled "Method and System for Providing Electrical Stimulation to a User"; U.S. application No.62/292,511 entitled "Stimulation System and Method" and filed on 8/2/2016; U.S. application No.62/442,350 entitled "Stimulation System and Method" and filed on 2017, 1, 4; U.S. application No.14/878,647 entitled "Electrode System for Electrical Stimulation" and filed on 8/10/2015; U.S. application No.15/059,095 entitled "Method and System for Providing Electrical Stimulation to a User" and filed on 2016, 3, 2; and U.S. application No.15/335,240 entitled "Electrode position System and Method" and filed on 2016, 10, 26, which are each incorporated herein by reference in their entirety; however, the electro-stimulation device may additionally or alternatively include any other suitable electrode positioning aspect and/or electrodes for providing stimulation. For example, variations of method 100 may be used for impedance monitoring in any other electrical stimulation device for any other suitable body region of a user in connection with any other suitable type of therapy.

The baseline state of the electro-stimulation device is preferably a non-stimulation state or a state in which the current through the stimulation path is below a threshold level for stimulation. In an example, the baseline state may be a deactivated state, a powered down state, an idle state, a standby state, or any other suitable state. A transition from the baseline state to the first impedance monitoring state may be triggered by transmission of a waveform definition for stimulation from the controller to the electro-stimulation device; however, the transition from the baseline state to the first impedance monitoring state (or any other state of the electro-stimulation device) may be triggered in any other suitable manner. In an example, the transition from the baseline state may occur using any one or more of: receiving a user input (e.g., at a controller, at a device) to turn an electro-stimulation device from a powered off state to an active state, receiving a user input (e.g., at a controller, at a device) to turn an electro-stimulation device from an idle state to an active state, receiving a user input (e.g., at a controller, at a device) to turn an electro-stimulation device from a standby state to an active state, detecting a change in a position of the electro-stimulation device (e.g., from a resting position to a position at a body of a user) with one or more motion sensors (e.g., an accelerometer, a gyroscope, an image-based sensor, an audio-based sensor, a temperature-based sensor, a force sensor, a pressure sensor, etc.), and any other suitable trigger.

The first impedance monitoring state preferably provides for monitoring of the impedance along the stimulation path according to the waveform definition prescribed for the electrical stimulation session of block S130. Thus, transitioning the electro-stimulation device from the baseline state to the first impedance monitoring state may include implementing a path impedance operation that provides impedance monitoring along the stimulation path (e.g., with respect to different electrodes, with respect to an electrode area, with respect to an interface between the electrodes and the user's body, etc.) according to one or more criteria. In addition to or instead of monitoring impedance along the stimulation path, the first impedance monitoring state may provide impedance monitoring through one or more other paths, such as a set of paths where each path is located between two adjacent electrical sections of a single physical electrode, or a set of paths where each path is located between one electrode and all other electrodes of the combined set.

As shown in fig. 2, in an example application of block S110, upon activation of the electro-stimulation device (e.g. turning on the stimulation device), the user may position a head-mountable portion (e.g. a headset) of the electro-stimulation device at his/her head region, with the electrodes of the head-mountable portion positioned approximately near the intended location for stimulation. The impedance (R) through the stimulation path to the user may be high before adjusting the position of the electrodes coupled to the head-mountable portion. In this example, activation of the electro-stimulation device involves transmission of waveform definitions from the controller to the electro-stimulation device, which controls the electro-stimulation session described in the example of block S130. In this example, following transmission of the waveform definition, the controller commands the electro-stimulation device to initiate measurement of impedance along the path in accordance with the waveform definition in accordance with the path impedance monitoring operation. However, alternative examples of block S110 may be implemented in any other suitable manner. For example, prior to adjusting the position of the electrodes coupled to the headgear-mountable portion, the impedance (R) through the stimulation path to the user may be low, where the low impedance indicates that the positions of the electrodes are not optimal (e.g., the electrodes are too close to each other or shorted together). In another example, the complex impedance (Z, not shown) or the frequency-dependent complex impedance (Z (f)), through the stimulation path, may not be within a desired range (e.g., indicating a range of electrodes in contact with the correct anatomical region of the head based on comparison to known electrical impedance tomography and/or electrical impedance plethysmography data; indicating a range of electrode-tissue interfaces for which a size or electrical characteristic is desired to initiate stimulation) prior to adjusting the position of the electrodes coupled to the head-mountable portion. Generally, impedances as used herein may alternatively or additionally include complex impedances or frequency-dependent complex impedances in addition to conventional resistances. Such complex impedance may be measured using techniques such as transmitting sinusoidal waveforms at varying or superimposed frequencies, or by extracting complex impedance information from the shape of voltage transients resulting from the transmission of current pulses.

Block S120 recites: during the first impedance monitoring state, directing, with the controller, an adjustment of a position of the electro-stimulation device at the body area of the user until a first impedance criterion associated with the first impedance monitoring state is met. Block S120 is used to coordinate impedance monitoring with readjustment of the electro-stimulation device until the impedance along the stimulation path is low enough to improve the chances of having an uninterrupted stimulation session in block S130.

In coordination with the adjustment of the position of the electro-stimulation device at the user' S body, block S120 may include outputting one or more current pulses by the electro-stimulation device during which the voltage parameters and/or the current parameters may be monitored to determine the impedance along the stimulation path. Block S120 preferably includes outputting a set of current pulses for the entire adjustment period, but may alternatively include outputting a single current pulse for the adjustment period. Alternatively, the output pulse may be a voltage pulse during which current parameters and/or voltage parameters may be monitored to determine the impedance along the stimulation path.

In variations in which the electrical stimulation device outputs a set of current pulses, the set of current pulses may include pulses having uniform pulse widths, or may alternatively include pulses having non-uniform pulse widths (e.g., one or more pulses may have a different width than other pulses in the set of current pulses). Additionally or alternatively, each pulse in a set of pulses can have the same amplitude as the other pulses in the set of pulses (e.g., 0.18mA zero peak amplitude, zero peak amplitude from 0.01mA to 0.50mA, etc.), or alternatively, one or more pulses in the set of pulses can have a different amplitude than the other pulses in the set of pulses. The set of current pulses may additionally or alternatively be provided at a constant frequency (e.g., with a constant time interval between pulses, a frequency between 2 and 20Hz, etc.), or alternatively a non-uniform time interval between pulses (e.g., a random time interval between pulses) may be provided. Still alternatively, the current pulses may be output whenever a sensor (e.g. accelerometer, gyroscope, magnetometer, force sensor, etc.) of the electro-stimulation device detects a change in position of the electro-stimulation device during the first impedance monitoring state. For example, a current pulse or set of current pulses may be output after each adjustment in a set of adjustments to the position of the electro-stimulation device, the adjustments being detected by above-threshold movement of the electro-stimulation device detected using an accelerometer. However, the set of current pulses may be output in any other suitable manner.

The set of current pulses preferably comprises biphasic current pulses, examples of which are shown in fig. 3, in order to avoid deviations in impedance measurements produced using constant current or monophasic pulses, and/or to facilitate controlled studies using pseudo-Electrical Stimulation (sham Electrical Stimulation) which at least partly consists of simulated Stimulation with a real amplitude of zero or very low, during which the problem of impedance and Electrode position has to be detected in a realistic manner, examples, variants and examples of which are described in us application No.14/470,683 entitled "Electrode System for Electrical Stimulation". However, the set of current pulses may additionally or alternatively include one or more monophasic pulses, pseudo-monophasic pulses, or pulses having alternative shapes.

When biphasic current pulses are used, the set of pulses may comprise biphasic pulses comprising inter-phase spacings, or may comprise biphasic pulses without inter-phase spacings. The electrodes may optionally be shorted together inside the device during the inter-phase intervals. Further, the biphasic pulse may have a square wave profile, an example of which is shown in fig. 3. However, in other variations, the biphasic pulse may have any other suitable profile (e.g., a saw-tooth profile, etc.).

In a variation, implementing the first impedance monitoring state may include implementing elements (e.g., components in software, components in hardware, components in firmware) of one or more digital-to-analog converters (DACs) for managing the electrical stimulation device, wherein the DACs convert the digital waveform definitions from the controller to an analog output (e.g., to an output stage comprising a voltage-controlled current source including an amplifier operable to take an input voltage from the DAC and produce a controlled current proportional to the input voltage through a stimulation path, to switch to an electrode of the electrical stimulation device for stimulation). Thus, as shown in fig. 4, one or more of blocks S110 and S120 may include implementing a first DAC management component that generates a set of current pulses for impedance monitoring as described above. In a variant, the first DAC management component may be implemented in software and generate a biphasic pulse whenever a portion of the waveform definition (or impedance monitoring state) has a value below a threshold current value, so that the impedance through the stimulation path can be checked even when the current output is low (e.g., using the total peak-to-peak voltage divided by the total peak-to-peak current). In a specific example, the current threshold is 0.3mA, such that whenever the current output is below 0.3mA, the first DAC management component with the DAC governs/controls the output of the biphasic current pulses; however, in variations of the particular example, the current threshold for the first DAC management component may have any other suitable current value or range of values (e.g., from 0mA to 1mA, etc.). In a variant, both the DAC and the output stage can only generate single phase or substantially single phase pulses, and/or single polarity or substantially single polarity outputs; in these variations, biphasic output current pulses may be generated by using a multiplex switch functionally between the output stage and the user, such that the polarity is switched between leading and trailing phases.

Thus, in the example of block S110, whenever the amount of current delivered through the stimulation path (e.g., specified by the waveform definition) is below a threshold amount of current, a biphasic current pulse is output during the first impedance monitoring state; however, the set of current pulses may additionally or alternatively be transmitted in any other suitable manner.

The first impedance criterion of the first impedance monitoring state is preferably an impedance or an impedance-based criterion relating to impedance measurements in a non-stimulation mode of the electro-stimulation device. In one variation, the impedance may be determined as the total peak-to-peak voltage measured during the biphasic pulse divided by the total peak-to-peak current output during the biphasic pulse. In another variation, the impedance/resistance may be measured in any other suitable manner.

In other variations, the impedance may alternatively be inferred indirectly based on the amount of current that may actually be delivered through the stimulation path. However, in block S120, impedance monitoring may be implemented in another manner.

The first impedance criterion is preferably more stringent than the third impedance criterion used in block S150, as described in more detail below, in order to provide more stringent requirements for initializing the stimulation than if the impedance for some reason increases above a threshold limit during the stimulation mode, the stimulation is reinitialized. In fact, the greater stringency in the first impedance criterion compared to the third impedance criterion can be based on the difficulty of implementing the impedance criterion. For example, setting the same impedance threshold for the first and third impedance criteria results in a third impedance criteria that is easier to implement (i.e., after a stimulation session has started or proceeded) because the impedance may drop after the initial start of stimulation. However, the first impedance criterion may alternatively be the same as the third impedance criterion of block S150, or may alternatively be less stringent than the third impedance criterion of block S150. For example, the device may be configured such that the measured impedance must be below a threshold limit of 10k Ω (e.g., a first impedance criterion) before entering the stimulation mode of block S130, but reinitialization of stimulation may occur when the measured impedance is below a threshold limit of 12k Ω (e.g., a third impedance criterion) after stimulation has been interrupted in block S140. However, the first and third impedance criteria may additionally or alternatively have any other suitable impedance threshold (e.g., 1k Ω, 5k Ω, 10k Ω, 15k Ω, etc.) or threshold condition for any other suitable range of impedances (e.g., 5-10k Ω, 8-12k Ω, etc.).

With respect to guiding the adjustment of the position of the electro-stimulation device at the user' S body in block S120, block S120 may include guiding the user to manually position the electro-stimulation device using one or more of visual guidance, auditory guidance, tactile guidance, and any other suitable form of guidance. In a first variation, the display of the controller (e.g., the display of the mobile computing device and the application executing at the mobile computing device) may be configured to provide real-time guidance for dynamically adjusting the position of the electro-stimulation device, an example of which is shown in fig. 5. Additionally or alternatively, in another variation, wherein the electrical stimulation device comprises a headset that positions the electrodes at the user's head, an audio output device (e.g., a beep element, a speaker element, etc.) coupled to the headset may be configured to provide guidance related to the positioning of the headset. In a first example, one or more of the beep frequency, pitch and loudness, or vibration frequency or amplitude may be reduced as the headset approaches an optimal position. In another example, the verbal instructions may be communicated through a speaker of the headset. However, in block S120, guidance for manual adjustment may be provided in any other suitable manner.

Optionally, block S120 may additionally or alternatively include automatic adjustment of the electrical stimulation device to provide the appropriate impedance through the stimulation path to initiate stimulation in block S130. In one such example, block S120 may include implementing a vibration motor (e.g., an eccentric rotating mass device) operable to vibrate an electrical stimulation device (e.g., a headphone portion of the electrical stimulation device) at the user' S body until a first impedance criterion is reached. However, automatic adjustment of the position of the electro-stimulation device may be achieved in block S120 in any other suitable manner.

As shown in FIG. 2, in an example application of block S120, once the path impedance operation has begun (in the example of block S110 above), the electro-stimulation device may be configured to generate a biphasic current pulse in coordination with an impedance measurement of the electro-stimulation device, wherein the impedance is measured by dividing a total peak-to-peak voltage measured during the biphasic pulse by a total peak-to-peak current output during the biphasic pulse. Thus, this example application allows for the collection of high quality impedance measurements even if the interface involving the electrode (e.g., electrode-tissue interface, electrode-saline interface, etc.) produces an electrochemical potential that would otherwise affect the impedance determination. Thus, the depicted example of block S120 implements an impedance/resistance focused criterion, rather than a current focused criterion associated with how much current may actually be delivered through the stimulation path.

In the example application of block S120 described above, concurrently with the biphasic-pulse-based impedance measurement, the example may further include guiding the user within an application executed at the user 'S mobile computing device (i.e., controller) to adjust the position of the head-mountable portion of the electro-stimulation device until contact between an electrode coupled to the head-mountable portion and the user' S head is improved. In this example, the guidance may comprise presenting a representation of the head mountable portion of the electro-stimulation device together with a representation of the electrodes relative to the head mountable portion, with an indication of which electrodes are out of contact, an example of which is shown in figure 5. When an impedance value is obtained that is below a threshold impedance value (e.g., 16k Ω, 5-25k Ω, etc.), an example application of method 100 may include transitioning the electrical stimulation device from the first impedance monitoring state to a stimulation mode, as described below with respect to block S130. However, alternative examples of block S120 may implement any other suitable impedance criteria for initiating stimulation according to block S130, or in any other suitable manner. In one example, the impedance criteria of block S120 and/or other impedance criteria described herein may also be implemented as a two-part criterion that includes hysteresis in order to reduce rapid cycling between the impedance monitoring state and the electrical stimulation mode. For example, the impedance criteria may require that the impedance initially be below an initial threshold, such as 15k Ω, yet briefly, but for a duration such as five seconds, remain below a slightly higher threshold, such as 20k Ω, in order to exit the impedance monitoring state.

1.2 methods-stimulation and impedance monitoring

Block S130 recites: upon satisfaction of the first impedance criteria, transitioning the electro-stimulation device from the first impedance monitoring state to a stimulation mode including a second monitoring state having second criteria, wherein the stimulation mode provides an electro-stimulation session to the user according to a set of waveform characteristics. According to blocks S110 and S120, once the impedance along the stimulation path is appropriate, block S130 is used to initiate and provide the stimulation session.

Transitioning the electro-stimulation device to the stimulation mode preferably includes effecting a stimulation session in accordance with the waveform definition transmitted to the electro-stimulation device by the controller.

In a variation, implementing the stimulation session according to the waveform definition may include implementing elements (e.g., components in software, components in hardware, components in firmware) of one or more digital-to-analog converters (DACs) for managing the electrical stimulation device, where the DACs convert the digital waveform definition from the controller to an analog output (e.g., to an output stage that includes a voltage-controlled current source that includes an amplifier operable to take an input voltage from the DAC and produce a controlled current proportional to the input voltage through a stimulation path, to switch to an electrode of the electrical stimulation device for stimulation).

Thus, as shown in fig. 4, block S130 may include implementing a second DAC management component that modulates waveform components related to abrupt changes in current output (e.g., abrupt changes from a high current state to a low current state or from a low current state to a high current state) in order to improve user comfort associated with the provided electrical stimulation. Thus, for waveform-defined features having a change in current value above a threshold (e.g., a maximum step value), the second DAC management component ramps the current down and/or ramps the current up according to a desired ramp rate. In one example, the second DAC management component is implemented as a software object that tracks step changes in the delivered current, and if a step change in current is detected, the second DAC management component converts the step change to an appropriate ramp up or ramp down change in current in order to enhance user comfort.

The threshold change in current that triggers the current ramping by the second DAC management component may be a fixed threshold across multiple users, or may alternatively be user-specific or demographic-specific. For example, in one example, a threshold change in current before ramping occurs may be set by the user during calibration of the electro-stimulation device, where the user may experience a different step change in current and a step indicating the onset of discomfort. In another example, a biological parameter of the user (e.g., skin thickness, touch receptor distribution, etc.) may be used to determine an appropriate threshold. In another example, the threshold change in current before ramping occurs may be set by the waveform definition and/or modified by data in the waveform definition during waveform transmission. However, the threshold change may alternatively be determined in any other suitable manner.

The ramp rate may be constant, regardless of the current step, over the course of the second DAC management component. Alternatively, the ramp rate parameter may depend on the current step (e.g., there may be an inverse relationship between the step and ramp rates). Further, the ramp rate for ramping up the current may be the same or different than the ramp rate for ramping down the current. Additionally or alternatively, the ramp may comprise a linear ramp or a non-linear ramp. However, the switching of the waveform definition by the second DAC management component may alternatively be implemented in any other suitable manner.

Additionally or alternatively, the second DAC management component may modulate the waveform components, including abrupt changes from a state where the current waveform has low energy (e.g., zero output or an oscillating waveform with an RMS value of 0.1 mA) to a state where the current waveform has high energy (e.g., an oscillating waveform with an RMS value of 1.0 mA), or vice versa. Thus, this embodiment of the second DAC management component ramps down the overall scale, energy or RMS value of the transmitted waveform and/or ramps up the overall scale, energy or RMS value of the transmitted waveform according to the desired ramp rate.

Additionally or alternatively, as shown in fig. 4, a third DAC management component may be included in the system of block S130 to deliver spurious stimuli during, for example, a clinical trial. The third DAC management component may be used to divert stimulation current through an internal short-circuited path, or to replace stimulation output specified by the waveform definition with a zero-amplitude or low-amplitude false output, while collecting impedance data and producing realistic system behavior, such as alerting the user when connection to the head is lost. The third DAC management component may be enabled by a user, or remotely, or may be enabled and disabled by data contained within the waveform definition. Additionally or alternatively, as shown in fig. 4, a fourth DAC management component may be included in the system of block S130 to scale the stimulus output according to the user input. Such scaling may be accomplished, for example, by applying a predefined multiplier or multipliers specified by waveform definitions to the DAC output for each of a set of amplitude levels that are user selectable (e.g., using a knob or slider control element on a user interface on controller 220), embodiments, variations, and examples of which are described in U.S. application No.15/059,095 filed 2016, 3, 2, which is incorporated herein by reference in its entirety.

The stimulation session of the stimulation mode is preferably achieved using electrodes wetted with saline; however, the stimulation session of the stimulation mode may alternatively be implemented using any other suitable type of electrodes. In embodiments, variations and examples, the use of electrodes as described in one or more of the following is performed: U.S. application 14/470,683 entitled "Electrode System for Electrical Stimulation" and filed on 27/8/2014; U.S. application No.14/470,747 entitled "Method and System for Providing Electrical Stimulation to a User"; U.S. application No.62/292,511 entitled "Stimulation System and Method" and filed on 8/2/2016; U.S. application No.62/442,350 entitled "Stimulation System and Method" and filed on 2017, 1, 4; U.S. application No.14/878,647 entitled "Electrode System for Electrical Stimulation" and filed on 8/10/2015; U.S. application No.15/059,095 entitled "Method and System for Providing Electrical Stimulation to a User" and filed on 2016, 3, 2; and U.S. application No.15/335,240 entitled "Electrode position System and Method" and filed on 2016, 10, 26; however, block S130 may additionally or alternatively implement any other suitable electrode system, or any system of transducers, such as ultrasound or light emitting elements for brain stimulation.

The stimulation session of the stimulation pattern of block S130 preferably includes Transcranial Electrical Stimulation (TES) configured to stimulate a brain region of the user in the form of at least one of transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), Transcranial Magnetic Stimulation (TMS), transcranial random noise stimulation (tRNS), transcranial variable frequency stimulation (tVFS), and any other suitable form of transcranial stimulation.

In a variation, the waveform of the stimulation pattern of block S130 may be associated with one or more of: direct Current (DC) stimulation; alternating current stimulation (AC); pulse sequence, random stimulation; pseudo-random stimulation; a basic pseudo-random noise stimulus; band-limited random noise stimulation; band-limited pseudo-random noise stimulation; variable Frequency Stimulation (VFS); a stimulus having a composite superimposed waveform; as well as any other suitable type of stimulus. The waveform of the stimulation may be defined by parameters including one or more of: amplitude, frequency, spectrum, pulse width, inter-pulse spacing, and any other suitable parameter, wherein the parameters are constant over at least a portion of the waveform. Additionally or alternatively, in some variations of block S130, parameters of the waveform may vary over at least a portion of the waveform. However, block S130 may include Providing Stimulation therapy with any other suitable type of waveform, embodiments, variations, and examples of which are described in U.S. application No.14/470,747, entitled "Method and System for Providing Electrical Stimulation to a User".

The Stimulation session of the Stimulation mode of block S130 may additionally or alternatively implement Method steps of waveform transformation, embodiments, variations and examples of which are described in U.S. application No.15/059,095 entitled "Method and System for Providing Electrical Stimulation to a User" and filed on 2016, 3, 2. However, the stimulation session of the stimulation pattern of block S130 may additionally or alternatively be implemented in any other suitable manner.

With respect to the second monitoring state of block S130, the second criterion may include a criterion with emphasis on current. In a variant, the current-emphasized criterion may be obtained by dividing the actual stimulation voltage (V) by the actual stimulation current (i)_{Practice of}) To measure the impedance. In another variation, the current focus criteria may include monitoring the current (i) attempted to be delivered_{Try to}) And the current (i) actually delivered_{Practice of}) The difference between them. In particular examples, the difference threshold may be an absolute difference, or may alternatively be a percentage difference (e.g., i |)_{Practice of}And i_{Try to}A 10% difference therebetween) or may be defined as the greater of a percentage difference and an absolute difference (e.g., a 10% or 0.1mA difference, whichever is greater). Thus, the second criterion may be associated with a determination of how much current can actually be delivered in a particular configuration of electro-stimulation device at the user's body. In this variation, e.g.Intercarpal current (i)_{Practice of}) Less than the current (i) attempted to be delivered_{Try to}) Beyond the threshold amount, the second criterion is not satisfied and block S140 is executed. However, as long as the delivered current (i) is attempted_{Try to}) At the actual current (i) delivered_{Practice of}) Is met, and the stimulation session of the stimulation pattern of block S130 continues. The second impedance may additionally or alternatively have a duration factor (e.g., the impedance and current threshold conditions must be maintained for a certain period of time before stimulation is suspended, or a certain number of measurements must be observed in a certain time window); however, the second monitoring criterion (and/or the first impedance monitoring criterion) may additionally or alternatively have any other suitable condition.

Additionally or alternatively, the stimulation mode of block S130 may implement a first DAC management component to generate biphasic current pulses (or other current pulses) for impedance measurement (e.g., in a low current portion of the waveform definition, etc.).

Additionally or alternatively, with respect to safety, the described methods and/or systems may implement a Multiplexer (MUX) array having a set of internal switches (e.g., analog switch solid state relays) configured to deliver desired current outputs to electrodes for stimulation and to short/deliver undesired currents back to the system. Thus, transients, anomalies, and/or undesirably high currents may be safely passed through alternate paths and away from the electrodes for stimulation to protect the user from unsafe currents; for example, if the system detects that the delivered current is above the current specified by the waveform definition by a given threshold, the system can react by shorting all the outputs together, ensuring that no current reaches the user, while otherwise alerting the user.

As shown in fig. 2, in an example application of block S130, once the controller of the system determines that the first impedance criterion has been met (e.g., by comparing the impedance to a threshold value, by requiring that the threshold condition not be met for a certain duration of time), the controller may issue a command to transition from the first impedance monitoring state and initiate the stimulation mode. In a particular example, the stimulation session includes a waveform defining component of Direct Current (DC) stimulation at a particular level, and because the DC level is above a threshold amount, the second DAC management component of the particular example implements a linear ramp to the DC level for user comfort. In a particular example, the first DAC management component of the particular example generates a biphasic pulse when the delivered current is below a current threshold (e.g., 0.3mA) when the current is ramped to a DC level in order to provide an accurate impedance measurement, but above the threshold current, the impedance is measured by dividing the actual stimulation voltage by the actual stimulation current delivered. Once stimulation is initiated in the stimulation mode, the measured impedance typically (but not necessarily) rises to a higher value over a short period of time due to the electrochemical reaction at the electrode-tissue interface, and then typically (but not necessarily) gradually falls over a longer period of time during stimulation (e.g., due to the electrochemical reaction and biological effects such as perforation or vasodilation of tissue near the electrode), as shown in fig. 3. However, variations of the particular example of block S130 may operate in any other suitable manner or produce any other suitable behavior.

1.3 method-impedance change detection and device readjustment

Block S140 recites: upon detecting that the second criterion is not met, transitioning the electro-stimulation device from the stimulation mode to the first impedance monitoring state. Block S140 provides for ceasing stimulation or attempting to output a current for stimulation when the current (e.g., related to the current vs actual current of the measurement attempt) or the impedance does not meet a desired threshold criterion.

In block S140, determining that the second criterion is not satisfied may include: comparing the actual currents i delivered_{Practice of}With the delivered trial current i_{Try to}And if at i_{Practice of}And i_{Try to}Above a threshold (e.g., a threshold percentage difference, a threshold absolute difference, etc.) transitions to a first impedance monitoring state. Additionally or alternatively, determining that the second criterion is not met may include determining an impedance by dividing the actual voltage by the actual current, and transitioning to the first impedance monitoring state if the impedance is greater than a threshold impedance value. However, it is determined that the firstBoth criteria may be performed in any other suitable manner.

In a variant, the second criterion may not be met due to conditions comprising one or more of the following: movement of the user during strenuous activity (e.g., performing a movement training mode while coupled to the electro-stimulation device); movement of the user during non-strenuous activity (e.g. the electro-stimulation device slides off of a location as the user moves during non-strenuous activity); removing the electro-stimulation device (e.g., by the user, by another entity) due to discomfort during stimulation; removal of the electro-stimulation device (e.g., by the user, by another entity) due to the intent to prematurely stop stimulation; impedance-related failures due to electrode contamination; impedance-related faults due to electrode saturation conditions (e.g., salt water, etc., including increased impedance due to drying); impedance-related faults due to improper coupling between the electrodes and other parts of the electro-stimulation device; impedance-related faults due to system electrical system faults; and any other suitable conditions that result in inappropriate impedance characteristics along the stimulation path.

In block S140, transitioning the electro-stimulation device from the stimulation mode to the first impedance monitoring state preferably comprises implementing the second DAC management component described in block S130 above, whereby the second DAC management component ramps the stimulation current suitably below the threshold current level associated with the first impedance monitoring state. In this variation, ramping down the current promotes user comfort such that discordant variations in current experienced at the electrode-tissue interface are not provided to the user. However, block S140 may optionally omit ramping the current down by the second DAC management component.

Additionally or alternatively, with respect to transitioning to the first impedance monitoring state, block S140 may include implementing a first DAC management component to generate a set of current pulses for determining an impedance of the electro-stimulation device in a low current state (or a zero current state). Similar to block S110 above, the first DAC management component having a DAC may be configured to provide biphasic pulses with selectable phase-to-phase spacing at a set frequency when the current drops below a threshold current limit during a transition from the stimulation mode to the first impedance monitoring state. However, the block S140 may optionally omit implementation of the first DAC management component, and may operate in any other suitable manner.

Similar to block S110 above, once the first impedance monitoring state has been reached (or before the first impedance monitoring state is reached), the controller and/or electro-stimulation device may be configured to direct adjustment of the electro-stimulation device at the user' S body region until the appropriate impedance characteristics are obtained along the stimulation path, similar to the methods described in blocks S110 and S120. However, the guidance for adjusting the electro-stimulation device at the user's body area may alternatively be implemented in any other suitable way.

As shown in figure 2, in the example application of block S140, once the head-mountable portion of the electro-stimulation device begins to lose contact with the user' S head (e.g. due to vigorous activity), the impedance begins to rise to a voltage that is not available at the output stage sufficient to drive the trial current i_{Try to}Through the level of the stimulation path and the current i actually delivered_{Practice of}Deviation from trial current i_{Practice of}. This condition is detected by an electro-stimulation device implementing the second criterion by: periodic monitoring (e.g., 10 times per second, 1 time per second, etc.) and comparing i_{Try to}And i_{Practice of}And if i_{Try to}And i_{Practice of}A difference in the threshold amount (e.g., 10%, 0.1mA, any percentage difference between 1-20%, any current difference between 0.02-0.5mA, etc.) having a threshold frequency (e.g., for a measurement of 30% within a given 1-second window, i.e., i._{Try to}And i_{Practice of}Significantly different), or have a threshold number of consecutive instances (e.g., i)_{Try to}And i_{Practice of}3 consecutive differences therebetween).

Thus, in the example of block S140, when a current deviation is detected, the electrical stimulation device begins to ramp down the stimulation current according to a programmed maximum ramp slope (e.g., 0.3mA per second) to transition from the stimulation mode to the first impedance monitoring state. Similar to the example described with respect to blocks S110 and S120, the electro-stimulation device then begins to provide biphasic current pulses and prompts the user to adjust the position of the head-mountable portion of the electro-stimulation device in a manner similar to that described above with respect to blocks S110 and S120.

In the example of block S140 above, one or more of the electrostimulation device and the controller may be configured to output one or more error notifications (e.g., visually with a display or light, tactilely, audibly, etc.). For example, one or more of the electrical stimulation device and the controller may provide a status condition or error notification when transitioning from the stimulation mode to the first impedance monitoring state. Additionally or alternatively, if the parameter of the delivered current is too high (e.g., no option to continue or restart stimulation), one or more of the electrical stimulation device and the controller may provide a status condition or error notification. Additionally or alternatively, one or more of the electro-stimulation device and the controller may provide a status condition or error notification if the parameter of the delivered current is too low (e.g. the head-mountable portion of the electro-stimulation device loses connection with the user's head). However, any other suitable status condition or error notification may be provided.

1.4 methods-transition to stimulation

Block S150 recites: upon detecting a third impedance criterion that satisfies the first impedance monitoring state, transitioning the electrostimulation device from the first impedance monitoring state to an electrostimulation mode. Block S150 provides for transitioning the electro-stimulation device back to the stimulation mode (or another appropriate state of the electro-stimulation device) once the impedance characteristic for the stimulation path is below a given threshold for the onset of stimulation.

In some variations, the implementation of the first impedance monitoring state in block S150 is similar to the implementation of the first impedance monitoring state in block S120. However, as indicated above at block S120, the third impedance criterion is preferably different from the first impedance criterion of block S120. In one variation, the third impedance criterion is less stringent than the first impedance criterion in order to provide more stringent requirements for initializing the stimulation than for reinitializing the stimulation after the impedance increases above a threshold limit during the stimulation mode (e.g., due to loss of contact during vigorous activity). Also, in practice, the greater stringency in the first impedance criterion compared to the third impedance criterion can be based on the difficulty of implementing the impedance criterion. For example, setting the same impedance threshold for the first and third impedance criteria results in a third impedance criteria that is easier to implement (i.e., after a stimulation session has started or proceeded) because the impedance may drop after the initial start of stimulation. In one example, the third impedance criterion and the first impedance criterion may each have an associated impedance threshold of 10k Ω, considering that an impedance of 10k Ω is more easily obtained once stimulation has started or progressed. In another example, the third impedance criterion may have an associated impedance threshold of 12k Ω to reinitialize stimulation as compared to the 10k Ω first impedance threshold required to begin a new stimulation session. However, as indicated above, each of the first and third impedance criteria may include a range of impedance values for initiating stimulation (e.g., the first impedance criteria may have an associated range of 5-10k Ω, while the third impedance criteria may have an associated range of 8-13k Ω). Similar to the criteria described in block S120 above, the impedance criteria of block S150 may have a factor associated with the duration or number of pulses. For example, in a first example, the third impedance criterion may require that the impedance remain below the threshold for 5 seconds before the stimulation reinitializes. In a second example, the third impedance criterion may require that the impedance remain below the threshold for 10 biphasic pulses. However, the third impedance criterion may additionally or alternatively have any other suitable condition to provide suitable performance of the electro-stimulation device and/or enhance user safety.

Further, the third impedance criterion may alternatively be the same as the first impedance criterion of block S120, or may alternatively be more stringent than the first impedance criterion of block S120.

Any one or more of the above blocks relating to implementing the first impedance monitoring state, providing stimulation, monitoring impedance/current, leaving the stimulation mode, re-implementing the first impedance monitoring state and/or re-entering the stimulation mode may be implemented in the participation of the controller, or independently of the controller (e.g. at the head mountable portion of the electro-stimulation device). For example, the method 100 may be implemented for a user who has placed a controller (e.g. a mobile device executing an application and in some cases communicating with the head mountable portion of the electro-stimulation device) at a remote location whilst performing a training activity using the head mountable portion of the electro-stimulation device. However, the method 100 may additionally or alternatively be implemented in any other suitable manner.

With respect to transitioning the electro-stimulation device to the electro-stimulation mode, block S150 may include resuming the stimulation session only at the point in block S140 at which the stimulation session was stopped. Optionally, block S150 may include continuing stimulation according to the modified stimulation session based on including one or more factors including: a duration of time during block S140 during which no stimulus is provided to the user; the cause of high impedance; an attempted current output prior to transitioning from the stimulation mode to the first monitoring state; user intent (e.g., the user may not want to continue stimulation); the amount of stimulation a user receives over a given period of time; detecting a biometric parameter of the user (e.g., with respect to a cardiovascular parameter, with respect to a neurological parameter, with respect to a respiratory parameter, with respect to a parameter indicative of pressure, etc.); and any other suitable factors.

For example, in a first example, if the user' S stimulation session is only interrupted for less than a threshold duration (e.g., 30 seconds), the stimulation session may resume at the point in block S140 where the stimulation session stopped.

Additionally or alternatively, if the user's stimulation session has been interrupted for more than a threshold duration of time (e.g., 10 minutes), the stimulation session may be resumed with the modification (e.g., stimulation at a point in time prior to the point at which stimulation was interrupted may be resumed, stimulation may be resumed with a change in intensity/amplitude, etc.). Additionally or alternatively, if the user's stimulation session is interrupted near the end of the stimulation session, the stimulation session may not resume because the desired effectiveness has been nearly achieved.

For example, in some applications, it may be desirable, for example for safety reasons, that the aggregated amount of at least one stimulation parameter of a stimulation session provided during a time window does not exceed a maximum limit. Likewise, the maximum limit for the aggregate value of stimulation parameters associated with blocks S130-S150 may be any one or more of the following: maximum dose per day (e.g., stimulation duration, cumulative charge density, etc.), maximum dose per shorter time unit (e.g., minutes, hours), and any other suitable maximum dose. In one example, a daily dose of 30 minutes is an acceptable tDCS dose, with higher doses increasing the chance of skin irritation and/or other side effects on the user. Further, when the cumulative amount of stimulation is subtracted from the maximum stimulation dose, the remaining allowable stimulation may be tracked with respect to the maximum limit. Here, the cumulative dose may be increased by additional electrical stimulation and decreased when no stimulation occurs (e.g., according to a logarithmic decay). Thus, maximizing the effect of electrical stimulation therapy given the maximum acceptable therapeutic limit may significantly benefit the user's rate of recovery/rehabilitation/learning/improvement. In variations where the electrical stimulation therapy includes TES, the maximum limit is preferably the maximum amount of charge or charge density that can be delivered to the user per unit time (e.g., a time window) (e.g., determined based on current amplitude, duration, duty cycle, and electrode path), or the maximum amount of total charge (e.g., current multiplied by total delivery time). Additionally or alternatively, the electrical stimulation provided within the time window may be transmitted and modulated such that at least a minimum amount of stimulation is always provided to the user within the time window (i.e., defined as less than the amount of stimulation does not play a role). For example, a minimum duration and/or duty cycle of the tDCS may always be provided to the user within a time window, such that the electrical stimulation therapy provided to the user always has a measurable effect on the user's neuroplasticity. Thus, blocks S130-S150 can deliver a limited amount of electrical stimulation therapy to the user in a manner that automatically provides electrical stimulation to the user when the user most requires electrical stimulation, and in a manner that has a measurable effect on the user' S neurological condition. Again, in some variations, blocks S130-S150 may substantially omit modulating a stimulation session according to a ceiling constraint with respect to session interruption due to impedance-related factors.

Similar to the method described above, transitioning back to the stimulation session may include implementing a second DAC management component that ramps the current for stimulation appropriately to a desired level. However, optionally, the stimulus may be restored in block S150 without ramping or otherwise implementing the second DAC management component.

In an example application, as shown in figure 2, once the impedance falls below a threshold impedance value during the first impedance monitoring state (after which the electro-stimulation device may enter an idle state (e.g. a "Good to go" state), however, if the impedance rises, the electro-stimulation device may enter a wait state (e.g. a "pause stimulation" state). once below the threshold impedance value (e.g. 12k Ω) along the stimulation path for a certain duration, the electro-stimulation device may transition back to the stimulation mode, resuming the stimulation session at the point of interruption according to the waveform definition.

In this example, rather than immediately setting the trial current value to the current value when stimulation is interrupted according to the waveform definition, the electro-stimulation device implements a second DAC management component to ramp up the current for stimulation according to a programmed maximum ramp slope (e.g., 0.3mA per second). As shown in fig. 2, as the stimulation progresses, the impedance typically (but not necessarily) drops gradually during the stimulation due to electrochemical reactions and biological effects. Stimulation may define a normal termination from the waveform if no other current or impedance deviations are experienced. Alternatively, if another deviation in current or impedance is experienced, the method 100 may repeat the implementation of blocks S130-S150.

In a variation, the method 100 may omit or rearrange the blocks described above based on the condition or state of the electro-stimulation device. For example, method 100 may omit implementing the first impedance monitoring phase after stimulation is interrupted due to high impedance, but implement other methods of detecting a change in position of the electro-stimulation device relative to the user's body and repositioning the electro-stimulation device. In one such example, the electro-stimulation device may cooperate with a location-determining device (e.g., an optical system, near field communication system, etc.) that detects and stores the location of the electro-stimulation device in association with appropriate impedance characteristics along the stimulation path, and tracks the relative location between the electro-stimulation device and the location-determining device during stimulation. Then, if the location changes, the controller may be configured to guide a readjustment of the location of the electro-stimulation device according to the location determination device until the correct location is reached. Optionally, the electro-stimulation device may be configured to deliver additional electrolyte solution (e.g., saline) to or through the electrodes in an attempt to reduce the impedance along the stimulation path. However, other variations of the method 100 may additionally or alternatively include any other suitable blocks or steps, re-arranging blocks, or omitting portions of blocks.

In one example of an optical position determining system, one or more cameras on controller 220 may be used to capture images or video of an electro-stimulation device located on or near the head. These images or videos may include reference points located on the electro-stimulation device, such as circular features, points, joints, angles, color patches, and/or features that may be used for other identification using techniques known in the art of computer vision. These images or videos may also include identifiable points on the head, such as eyes, nose, ears, crown of the head, inion, pre-ear points, and/or other points, which may be identified using techniques known in the art of computer vision and facial recognition. The controller 220 may create an internal virtual model of the actual head and electro-stimulation device location and calculate the optimal location of the electro-stimulation device based on the intended use, the intended placement, or information specific to the user and/or information informed by functional neurophysiological measurements, such as EMG potentials triggered by Transcranial Magnetic Stimulation (TMS). Controller 220 may use the model of the actual and optimal locations to guide the user in readjusting the location of the electro-stimulation device.

Those skilled in the art of biological signaling will recognize from the foregoing detailed description and drawings and claims that modifications and changes may be made to the preferred embodiment of the method 100 without departing from the scope of the method 100.

2. System for controlling a power supply

As shown in fig. 6A and 6B, embodiments of a system 200 for providing electrical stimulation to a user may include one or more of the following: an electrical stimulation device 210 configured to provide a stimulation session to a user and to monitor impedance characteristics along a stimulation path associated with the stimulation session; and a controller 220 coupled to the electro-stimulation device, wherein the controller is configured to control the provision and modulation of the stimulation session to the user in accordance with the waveform definition and the monitored impedance characteristics. The system 200 is preferably configured to perform embodiments of the method 100 described above, but may additionally or alternatively be configured to perform any other suitable method, including methods described in one or more of the following: U.S. application 14/470,683 entitled "Electrode System for Electrical Stimulation" and filed on 27/8/2014; U.S. application No.14/470,747 entitled "Method and System for Providing Electrical Stimulation to a User"; U.S. application No.62/292,511 entitled "Stimulation System and Method" and filed on 8/2/2016; U.S. application No.62/442,350 entitled "Stimulation System and Method" and filed on 2017, 1, 4; U.S. application No.14/878,647 entitled "Electrode System for Electrical Stimulation" and filed on 8/10/2015; U.S. application No.15/059,095 entitled "Method and System for Providing Electrical Stimulation to a User" and filed on 2016, 3, 2; and U.S. application No.15/335,240 entitled "Electrode position System and Method" and filed on 2016, 10, 26.

The system 200 preferably includes embodiments, variations and examples of system elements as described in the following documents: U.S. application No.62/292,511 entitled "Stimulation System and Method" filed on 8/2/2016 and U.S. provisional application serial No.62/442,350 entitled "Stimulation System and Method" filed on 4/1/2017, each of which is incorporated herein by reference in its entirety. The system 200 may additionally or alternatively include elements described in one or more of the following: U.S. application 14/470,683 entitled "Electrode System for Electrical Stimulation" and filed on 27/8/2014; U.S. application No.14/470,747 entitled "Method and System for Providing Electrical Stimulation to a User"; U.S. application No.62/292,511 entitled "Stimulation System and Method" and filed on 8/2/2016; U.S. application No.62/442,350 entitled "Stimulation System and Method" and filed on 2017, 1, 4; U.S. application No.14/878,647 entitled "Electrode System for Electrical Stimulation" and filed on 8/10/2015; U.S. application No.15/059,095 entitled "Method and System for Providing Electrical Stimulation to a User" and filed on 2016, 3, 2; and U.S. application No.15/335,240 entitled "Electrode position System and Method" and filed on 2016, 10, 26.

The electrostimulation device 210 is preferably in communication with the controller 220 and is used to deliver electrostimulation to the user through a set of electrodes 211. Electrical stimulation apparatus 210 is preferably configured to generate and provide TES therapy, but may additionally or alternatively be configured to provide any other suitable electrical stimulation therapy, as described with respect to the methods described above. Preferably, electrostimulation device 210 includes an electrode array 221, but may alternatively include a single electrode. The controller 220 is operable to output a current value based on the set current output according to the waveform definition, wherein the output value is set according to a computing system (e.g., a central processing unit, a microcontroller, etc.).

In an example, as shown in fig. 7A and 7B, and with respect to impedance measurements, electrical stimulation device 210 and controller 220 may include an electronic configuration that supports one or more of a current limiting resistor 221 that limits the output current despite any fault or error in the software/system, wherein the value of the current limiting resistor determines the maximum allowable current output; a first node 222 at which a voltage can be measured IN order to sense a current through the stimulation path (e.g., from STIM _ OUT to STIM _ IN/ISENSE with a minimum 14-bit resolution, 10 times per second), wherein the current value is used with the voltage measurement to calculate an impedance; a second node 223 for measuring a voltage (e.g., with a minimum 14 bits of resolution, 10 times per second), wherein the voltage value is used with the current measurement from 222 to calculate an impedance; and a voltage controlled current output 224 that can deliver current to a user through a normally open switching device (e.g., an analog switch solid state relay) in series with the electrodes, an example of which is shown in fig. 7B. IN this example, the stimulation path is from STIM _ OUT to STIM _ IN/ISENSE; however, the stimulation path may additionally or alternatively be defined in any other suitable manner (e.g., by another ground path).

In an exemplary embodiment such as that shown in fig. 7A, the output stage 226 may be referenced to a 1V reference 227 instead of ground, so that in addition to being able to apply a normal full-scale positive voltage, the output stage 226 may apply a small negative voltage on the stimulation path when necessary, without having to reconfigure any multiplexers or switches after the output stage. The output stage 226 may generate a small negative voltage (in this example, <1V) to overcome the electrochemical polarization at the electrode-electrolyte interface, if necessary. For example, if output stage 226 is dominated by a DAC to maintain a constant zero current on the user's body area, but if electrode polarization has occurred (e.g., if output stage 226 applies a zero voltage such that a non-zero current will flow), output stage 226 with reference 227 is operable to apply a small negative voltage to maintain a constant zero current.

The method 100 and system 200 of the preferred embodiments and variations thereof may be at least partially embodied and/or implemented as a machine configured to receive a computer-readable medium storing computer-readable instructions. The instructions are preferably executed by computer-executable components that are preferably integrated with one or more portions of the system 200 and the processor and/or controller. The computer readable medium may be stored in the cloud and/or on any suitable computer readable medium, such as RAM, ROM, flash memory, EEPROM, optical devices (CD or DVD), hard drives, floppy drives, or any suitable device. The computer-executable components are preferably general-purpose or special-purpose processors, but any suitable special-purpose hardware or hardware/firmware combination device may alternatively or additionally execute instructions.

The figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to preferred embodiments, example configurations, and variations thereof. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

As will be recognized by those skilled in the neuromodulation art from the foregoing detailed description and from the drawings and claims, modifications and variations can be made to the preferred embodiments of the present invention without departing from the scope of the invention as defined in the following claims.

Claims

1. A system for providing electrical stimulation to a user, the system utilizing an electrical stimulation device in communication with a controller, the system comprising:

means for transitioning the electro-stimulation device from a baseline state to a first impedance monitoring state upon activation of the electro-stimulation device;

means for directing, with the controller, adjustment of the position of the electro-stimulation device at the user's head region during the first impedance monitoring state until a first impedance criterion associated with the first impedance monitoring state is met;

means for transitioning the electro-stimulation device from the first impedance monitoring state to a stimulation mode comprising a second monitoring state having second criteria when the first impedance criteria are met, wherein the stimulation mode provides an electro-stimulation session to the user according to a set of waveform characteristics;

means for transitioning the electro-stimulation device from the stimulation mode to the first impedance monitoring state at a first point in time upon detecting that the second criterion is not satisfied; and

means for transitioning the electro-stimulation device from the first impedance monitoring state to the stimulation mode at a second point in time upon detecting a third impedance criterion that meets the first impedance monitoring state;

wherein transitioning to the first impedance monitoring state comprises generating a set of biphasic current pulses at the electro-stimulation device, and measuring an impedance of a stimulation path through the electro-stimulation device by dividing a total peak-to-peak voltage by a total peak-to-peak current for each of the set of biphasic current pulses.

2. The system of claim 1, wherein implementing the first impedance criterion includes comparing impedance measurements on a subset of the set of biphasic current pulses to a threshold impedance value, and transitioning the electrical stimulation device from the first impedance monitoring state to the stimulation mode if the impedance measurements are below the threshold impedance value for a duration of time.

3. The system of claim 1, wherein implementing the first impedance monitoring state includes implementing a two-part hysteresis criterion for reducing cycling between the stimulation mode and at least one of the first impedance monitoring state, the second monitoring state.

4. The system of claim 3, wherein implementing the two-part hysteresis criterion includes requiring the impedance to initially fall below an initial threshold and then remain below a second, higher threshold for a duration of time.

5. The system of claim 1, wherein implementing the first impedance criterion includes comparing impedance measurements on a subset of the set of biphasic current pulses to a threshold impedance value, and transitioning the electrical stimulation device from the first impedance monitoring state to the stimulation mode if a specified number of consecutive impedance measurements are below the threshold impedance value.

6. The system of claim 1, wherein directing, with the controller, adjustment of the position of the electro-stimulation device at the user's head region comprises implementing an optical position determination system operable to: 1) facilitating creation of an internal virtual model of the head region and the location of the electro-stimulation device, and 2) determining an optimal location for the electro-stimulation device.

7. The system of claim 1, wherein directing with the controller the adjustment of the position of the electro-stimulation device at the head region of the user comprises directing visually with a display of the controller the user to adjust the position of a head-mountable portion of the electro-stimulation device.

8. The system of claim 1, wherein the first impedance monitoring state comprises measuring impedance with the electro-stimulation device according to a first technique, and wherein the second monitoring state comprises measuring impedance with the electro-stimulation device according to a second technique different from the first technique.

9. The system of claim 8, wherein the first technique comprises dividing a peak-to-peak voltage associated with a biphasic current pulse output by the electrical stimulation device by a peak-to-peak current, and wherein the second technique comprises at least one of: 1) dividing the actual voltage by the actual delivered current from the electro-stimulation device during the stimulation mode, and 2) comparing the attempted current to the actual current delivered during the stimulation mode.

10. The system of claim 1, wherein providing the electrical stimulation session includes implementing a digital-to-analog converter (DAC) management component that automatically modulates at least one of the set of waveform characteristics involving abrupt changes in current output from the electrical stimulation device.

11. The system of claim 10, wherein the DAC management component utilizes a first waveform characteristic that includes a step increase in current output with a first linear ramp and a second waveform characteristic that includes a step decrease in current output with a second linear ramp.

12. The system of claim 1, wherein implementing at least one of the first impedance monitoring state, the stimulation mode, and the second monitoring state includes implementing a multiplexer having a set of switches operable to pass an undesired current output away from the user and to the system.

13. The system of claim 1, wherein the first impedance criterion of the first impedance monitoring state has a first impedance value, and wherein the third impedance criterion of the first impedance monitoring state has a second impedance value that is greater than the first impedance value.

14. The system of claim 1, wherein the first impedance criterion of the first impedance monitoring state has a first impedance value, and wherein the third impedance criterion of the first impedance monitoring state has a second impedance value equal to the first impedance value.

15. The system of claim 1, wherein transitioning the electrical stimulation device from the first impedance monitoring state to the stimulation mode comprises resuming the electrical stimulation session at an interruption point associated with the first point in time.

16. The system of claim 1, wherein transitioning the electrical stimulation device from the first impedance monitoring state to the stimulation mode comprises calculating a duration of time between the first point in time and the second point in time, and resuming a modified version of the electrical stimulation session, the modified version determined based on the duration of time.

17. A system for providing electrical stimulation to a head region of a user, the system comprising:

an electro-stimulation device having a head-mountable portion and a set of electrodes reversibly coupled to the head-mountable portion, the electro-stimulation device being operable between a baseline state, a first impedance monitoring state and a stimulation mode having a second monitoring state, wherein:

the first impedance monitoring state comprises a first set of impedance criteria and is accessible under at least one of the following conditions: a) detecting activation of the electro-stimulation device and b) not meeting an impedance criterion of the second monitored state during the stimulation mode;

when at least one of the first set of impedance criteria of the first impedance monitoring state is met, the stimulation pattern provides a stimulation session with a waveform definition to the head region of the user, wherein the first impedance monitoring state and the stimulation pattern implement a first digital-to-analog management component that generates a set of biphasic current pulses for measuring impedance when a current output is below a current threshold; and

a controller that transmits the stimulation waveform definition and, in cooperation with the first impedance monitoring state, directs adjustment of the set of electrodes at the head region of the user.

18. The system of claim 17, wherein the head-mountable portion of the electro-stimulation device includes a pair of ear pads coupled to a bridge that is coupled to the set of electrodes and positions the set of electrodes on the motor cortex region of the user during operation.

19. The system of claim 17, wherein the stimulation pattern implements a second digital mode management component that converts waveform characteristics associated with a step change in current to waveform characteristics having a linear ramp in current.

20. The system of claim 19, further comprising: a third digital-to-analog management component operable to perform at least one of: diverting stimulation current through an internal short-circuit path of the electro-stimulation device, and replacing stimulation outputs defined by the waveform with dummy outputs in coordination with collecting impedance data.

21. The system of claim 20, further comprising: a fourth digital-to-analog management component operable to scale stimulation output based on user input at the controller.

22. The system of claim 17, wherein the controller comprises at least one portion implemented in an application executed at the user's mobile computing device and coupled to the electro-stimulation device.